Polymeric emulsifiers suitable for use in forming water-in-oil emulsions, also known as invert or inverse emulsions, are highly valuable in many diverse fields. While multiple predominantly hydrophobic or low HLB surfactants are useful in forming these emulsions, polymeric compounds in particular have been found to be highly efficacious in this application. Among the commercially useful compounds are polyisobutylene succinimide (PIBSA) ethanolamides, as well as the branched and linear polyalkoxylene polyhydroxystearic acid copolymers described in U.S. Pat. No. 4,203,877. While these compounds form highly resilient inverse emulsions in a variety of applications ranging from cosmetics to explosives formulations, they are limited in some instances by their moderate structural integrity and labile chemical bonds. In particular, we have found that currently known inverse emulsifiers are degraded into non-useful components by the action of strong acids or bases. For example, we have found that emulsifiers essentially comprising polyethylene oxides copolymerized with polyhydroxystearic acid are incapable of forming stable invert emulsions in which the encapsulated phase is a hydrochloric acid solution, especially when exposed to elevated temperatures. Even though emulsions of this nature are currently of commercial interest in areas, such as oil recovery, there is no suitable material with a high degree of stability towards strongly alkaline or acidic environments. Specifically, we have produced emulsifiers comprised of ether linkages which withstand chemical assault under conditions in which ester and amide bonds are cleaved or degraded. We envision these emulsifiers as being particularly useful in harsh or demanding environments, such as under strongly acidic conditions at elevated temperatures such as those found in subterranean wells or within the machinery of industrial processes where these temperatures may be encountered. The surfactants described herein also benefit from additional favorable characteristics, such as ease and affordability of synthesis, an anticipated low toxicity, and a low pour point allowing room temperature processing. The present invention provides an invert emulsifier with improved functionality and decreased environmental impact.